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        General >> Problems >> Cosworth Alternator or Battery problem?
        
(Message started by: KeithCEng on Sep 10^th, 2008, 6:20pm)

Title: Cosworth Alternator or Battery problem?
Post by KeithCEng on Sep 10^th, 2008, 6:20pm

Evening All!

I'm only doing short trips in my P Reg Cossie at present and sometimes it is left unused on my driveway for a couple of days. I have a solar trickle charger plugged into the cigarette lighter that produces about 50mA in overcast daylight conditions and about 300mA in full sunlight. About once a week, I take her for a blast up the local motorway (about 10 miles round trip) but despite having a new battery in April this year (another Halfords HCB097!), I still find her 'dead' some mornings. I have just purchased a DC Clamp Ammeter and today used it to check charging current into the Battery:

At tickover (750 RPM), effective current into the Battery was 6A with only the Radio switched on - the voltage was 14.05V; Still at 750 RPM, I then switched on full headlights/Fogs and both heated seats - Current into the Battery was 3A and voltage dropped to 12.8V; I then added Front and Rear heated screens to the load (still at 750 RPM) and the voltage dropped to 11.8V with 23A now flowing OUT of the Battery!

Keeping the same electrical load, I increased the revs to 2000 RPM - battery voltage climbed to 13.0V and current INTO the battery was 5A; Then I added the internal Fan (on max) to the load (still at 2000 RPM) - Battery voltage dropped to 11.6V and current OUT of the Battery was 17A. Finally, I switched everything off (except the Engine at 750 RPM!) - Battery voltage climbed to 13.9V and current INTO the Battery was 35A.

Is the problem Alternator based/Battery based or simply insufficient use of the car?

Title: Re: Cosworth Alternator or Battery problem?
Post by joe-satch on Sep 10^th, 2008, 6:51pm

hi,sounds like the alt is having trouble coping with the load,on my mk3 granada last week..i did a test..only 11.8v at the battery terminals....with hi revs,tryed a spare voltage regulater first...still the same....no good....fitted a new alt...now 14.3v...and coping with the load very nicely. :).regards den.

Title: Re: Cosworth Alternator or Battery problem?
Post by KeithCEng on Sep 10^th, 2008, 7:40pm

Many thanks for that info Den.

Keith

Title: Re: Cosworth Alternator or Battery problem?
Post by joe-satch on Sep 12^th, 2008, 12:07pm

your most welcome keith,good luck to you. :).regards den. :).